Photodetector and Electronic Apparatus

The present disclosure relates to a photodetector and an electronic apparatus.

A device that has a stacked structure in which an element substrate and a readout circuit substrate are stacked and photoelectrically converts entering light is proposed (PTL 1).

PTL 1: Japanese Unexamined Patent Application Publication No. 2021-89978

A device that detects light is expected to have improved performance.

It is desired to provide a photodetector having a satisfactory performance.

A photodetector according to an embodiment of the present disclosure includes a plurality of pixel units, the plurality of pixel units each including: a photoelectric conversion layer configured to output a photocurrent by photoelectric conversion, a readout circuit configured to output a first signal based on a first photocurrent, the first photocurrent being outputted by the photoelectric conversion layer, and an AD conversion circuit configured to output a second signal based on a second photocurrent, the second photocurrent being outputted by the photoelectric conversion layer.

An electronic apparatus according to an embodiment of the present disclosure includes an optical system and a photodetector that receives light transmitted through the optical system. The photodetector includes a plurality of pixel units, the plurality of pixel units each including a photoelectric conversion layer configured to output a photocurrent by photoelectric conversion, a readout circuit configured to output a first signal based on a first photocurrent, the first photocurrent being outputted by the photoelectric conversion layer, and an AD conversion circuit configured to output a second signal based on a second photocurrent, the second photocurrent being outputted by the photoelectric conversion layer.

1. First Embodiment 2. Second Embodiment 3. Modification Examples 4. Usage Examples 5. Practical Application Examples In the following, some embodiments of the present disclosure are described in detail with reference to the drawings. It is to be noted that the description is given in the following order.

1 FIG. 1 1 1 1 1 220 220 220 is a diagram illustrating an example of a schematic configuration of a photodetector according to a first embodiment of the present disclosure. The photodetectoris a device that enables detection of entering light. The photodetectorincludes a plurality of pixels each having a photoelectric conversion section (photoelectric conversion element). For example, the photoelectric conversion section of each pixel is a photodiode (PD) and is configured to photoelectrically convert light. The photodetectormakes it possible to receive light transmitted through an optical system including an optical lens (not illustrated) and to generate a signal. The photodetectorincludes a plurality of pixel units PU each including a plurality of pixels, and is configured to generate a signal by photoelectrically converting entering light. The photodetectorincludes a region (a pixel array) in which the plurality of pixel units PU is arranged two-dimensionally. For example, the pixel arrayincludes a plurality of pixel units PU arranged in a matrix, and it can also be said that the pixel arrayis a light receiving region.

1 1 1 The photodetectoris a device that enables distance measurement, and is configured to perform distance measurement using, for example, an FMCW (Frequency Modulated Continuous Wave) method. The photodetectormakes it possible to transmit and receive, via the optical system, an optical signal that is to be a modulated light having a modulated frequency, and to measure a distance to a measurement target, a speed of the measurement target, or the like. For example, the photodetectoris applicable as an FMCW-LiDAR (Light Detection and Ranging).

1 1 As one example, the photodetectordetects, for each pixel unit PU, a distance to an object (a subject) that is a measurement target and generates image data (distance image data) related to the distance to the object. For example, it is possible for the photodetectorto generate a depth map (Depth Map).

1 1 1 1 In addition, the photodetectoris configured to capture an image of the subject. The photodetectortakes in entering light (image light) from the subject via the optical system including an optical lens. It is possible for the photodetectorto capture the image of the subject formed by the optical system. The photodetectoris also applicable to various electronic apparatuses having an imaging function, such as a digital still camera, a video camera, or a mobile phone.

1 1 1 As one example, the photodetectorgenerates image data related to the image of the subject using a signal outputted from each pixel unit PU. It is possible for the photodetectorto generate image data indicating a gray scale value of each pixel. For example, the photodetectoris configured to generate a short-wave infrared image (an SWIR image).

1 1 1 For example, the photodetectorincludes a photonic integrated circuit (PIC: Photonic Integrated Circuit). It is possible to manufacture the photodetectorusing a substrate including silicon (a silicon substrate, an SOI (Silicon On Insulator) substrate, or the like.), utilizing silicon photonics technology. For example, the photodetectorhas a structure (a stacked structure) in which a plurality of substrates is stacked.

1 FIG. 1 200 210 220 230 1 200 210 As illustrated in, the photodetectorincludes a light source section, an optical element, a pixel array, and a signal processing section. The photodetectormakes it possible to cause the light source sectionand the optical elementor the like to irradiate a measurement target with an optical signal having a modulated frequency (laser light), and to receive the optical signal reflected and delayed from the measurement target.

1 200 220 For example, in the photodetector, a reference light branched (separated) from the light outputted from the light source sectionand a reflected light (returned light) reflected from the measurement target enter (are inputted to) the pixel array, and an electric signal having a frequency corresponding to a difference between a frequency of the reference light and that of the reflected light is detected. The electric signal generated by receiving the reflected light from the measurement target is a signal corresponding to the distance to the measurement target.

220 210 230 200 1 1 220 230 1 200 210 220 230 For example, the pixel array, the optical element, the signal processing section, or the like are provided separately on a plurality of substrates. The light source sectionmay be mounted on the photodetectoror may be provided outside the photodetector. It is to be noted that the pixel array, the signal processing section, or the like may be provided on one substrate. The photodetectormay be configured as a light detecting system including the light source section, the optical element, the pixel array, the signal processing section, or the like.

200 200 200 200 1 FIG. The light source sectionillustrated inis configured to generate an optical signal. For example, the light source sectionincludes a light emitting element and is configured to output an optical signal (laser light). As one example, the light source sectionincludes a variable laser light source and is configured to emit light to the measurement target. The light source sectionmay include a modulation section configured to modulate a frequency of the optical signal.

200 200 200 The light source sectionmay include, as the modulation section, a modulator (Modulator) configured using, for example, a Mach-Zehnder interferometer (Mach-Zehnder Interferometer). It is possible for the light source sectionto generate laser light having a modulated frequency and to emit the laser light having the modulated frequency. In other words, the light source sectionmakes it possible to generate and output a signal (chirp signal) having a frequency that changes continuously over time.

200 210 1 200 200 210 200 220 200 200 220 The light source sectionoutputs, to the optical element, the output light that is to be the optical signal having a modulated frequency. In the photodetector, for example, the output light from the light source sectionis branched (separated) by a splitter. A portion of the output light from the light source sectionis transmitted to the optical elementside, and another portion of the output light from the light source sectionis transmitted to the pixel arrayside as a reference light (local light). For example, a reference light having 50% of the power (light intensity) of the output light from the light source sectionis divided from the output light from the light source sectionand inputted to (entering) the pixel array.

210 200 210 210 210 The optical elementis configured to output the optical signal transmitted from the light source section. The optical signal (laser light) having a modulated frequency is propagated to the optical element. It is possible for the optical elementto output the optical signal that is the laser light having a modulated frequency to an outside as output light (irradiation light). The optical elementis an antenna configured to transmit an optical signal, and makes it possible to irradiate the measurement target with the laser light having a modulated frequency.

4 FIG. 210 211 212 212 211 211 211 212 211 211 1 212 As described below (see), the optical elementincludes a plurality of diffraction gratingsand a plurality of heaters. A heateris provided adjacent to the diffraction gratingsand is configured to heat each diffraction grating. As a result of the diffraction gratingbeing heated by the heater, a refractive index of the diffraction gratingis changed, thereby changing a traveling direction of the optical signal emitted from the diffraction grating. In the photodetector, it becomes possible to perform scanning (a scan) on the laser light that is the optical signal by temperature control or the like using the heater.

220 200 The pixel arrayincludes a plurality of pixel units PU. The pixel units PU each include a photoelectric conversion section and is configured to detect entering light. Each pixel unit PU is configured to receive a reference light from the light source sectionand a reflected light from an object as a measurement target, to generate an electric signal, and to output the electric signal as a signal related to the distance to the object (referred to as a distance measurement signal).

200 For example, the pixel unit PU includes a balanced photodiode and is configured to convert an optical signal into an electric signal. The pixel unit PU is configured to generate the distance measurement signal that is based on the optical signal from the light source sectionand the optical signal reflected from the object.

2 FIG. 2 FIG. 2 FIG. 1 2 is a diagram describing an example of a signal generated by the photodetector according to the first embodiment. In, a vertical axis indicates a frequency of the optical signal that is a chirp signal, and a horizontal axis indicates time.illustrates an optical signal Sthat is a transmission light to the measurement target, and an optical signal Sthat is a reception light from the measurement target.

1 2 230 1 The distance measurement signal generated in the pixel unit PU is a signal (also referred to as a beat signal) having a frequency corresponding to a difference between the frequency of the optical signal Sand the frequency of the optical signal S. The pixel unit PU includes an AD conversion circuit (an AD conversion section) and allows outputting, to the signal processing section, the distance measurement signal converted into a digital signal by the AD conversion circuit. In the photodetector, it is possible to calculate the distance to the measurement target, the speed of the measurement target, or the like, using the distance measurement signal.

220 230 In addition, the pixel unit PU is configured to generate an electric signal based on an amount of light received from an object, and to output the electric signal as a signal (referred to as an imaging signal) related to the image of the object (the subject). The imaging signal is a signal related to a gray scale value. It is possible for each pixel unit PU disposed in the pixel arrayto generate and output a distance measurement signal and an imaging signal to the signal processing section.

230 230 230 230 The signal processing sectionis a signal processing circuit and is configured to perform signal processing. The signal processing sectionincludes a circuit that performs various types of signal processing on the signal outputted from the pixel unit PU. The signal processing sectionincludes a calculation circuit, a memory circuit, or the like. The signal processing sectionmay include a processor and a memory.

230 220 1 230 The signal processing sectionanalyzes a frequency (a beat frequency) of the distance measurement signal outputted from each pixel unit PU in the pixel array, thereby making it possible to calculate a distance between the photodetectorand the measurement target. In addition, the signal processing sectionmakes it possible to calculate a speed (a relative speed) of the measurement target using a Doppler shift of light.

230 As one example, the signal processing sectioncalculates the speed of the measurement target on the basis of the beat frequency in a case where the frequency of the laser light is increased over time, that is, in the case of an up-chirp, and on the basis of the beat frequency in a case where the frequency of the laser light is decreased over time, that is, in the case of a down-chirp.

230 230 1 For example, the signal processing sectionmakes it possible to emit a laser light that is an optical signal having a modulated frequency in a form of a triangular wave and to calculate the speed of the measurement target, the distance to the measurement target, or the like by using the beat frequency of the beat signal in each case of the up-chirp and the down-chirp occurring in succession. For example, the signal processing sectioncalculates the distance between the photodetectorand the measurement target, or the like using the beat frequency obtained by fast Fourier transform (FFT) processing.

230 230 The signal processing sectionis configured to perform signal processing such as AD (Analog Digital) conversion and CDS (Correlated Double Sampling) on the imaging signal outputted from each pixel unit PU. In addition, the signal processing sectionmakes it possible to perform various signal processing such as noise reduction processing, interpolation processing, or gray scale correction processing on the imaging signal of each pixel unit PU.

230 230 As described above, it is possible for the signal processing sectionto perform signal processing on the distance measurement signal of each pixel unit PU and to generate the distance image data representing the distance to the subject. In addition, the signal processing sectionmakes it possible to perform signal processing on the imaging signal of each pixel unit PU, and to generate image data representing the image of the subject.

230 230 230 In addition, the signal processing sectionis configured to perform processing of synthesizing the imaging signal and the distance measurement signal for each pixel unit PU. As one example, the signal processing sectionperforms processing of adding the distance to the subject detected for each pixel unit PU to the image data representing the image of the subject. For example, the signal processing sectionmakes it possible to generate, as a signal value (a pixel value) of each pixel during a frame period, image data including gray scale information and distance information regarding each pixel.

230 1 230 230 200 200 230 210 The signal processing sectionis also a control section and is configured to control each section of the photodetector. It is possible for the signal processing sectionto include a circuit such as a PLL (Phase Locked Loop) or a DAC (Digital to Analog Converter). For example, the signal processing sectionis configured to supply a signal controlling the light source sectionto the light source section. In addition, the signal processing sectionis configured to control scanning of the optical signal by the optical element, generation and processing of the distance measurement signal and the imaging signal by the pixel unit PU, or the like.

3 FIG. 3 FIG. is a diagram illustrating a configuration example of a pixel unit in the photodetector according to the first embodiment. The pixel unit PU includes a pixel that allows outputting a distance measurement signal (referred to as a distance measurement pixel Pa) and a pixel that allows outputting an imaging signal (referred to as an imaging pixel Pb). In the example illustrated in, the pixel unit PU includes one distance measurement pixel Pa and two imaging pixels Pb. It is to be noted that the number and arrangement of the distance measurement pixel Pa and the imaging pixel Pb in the pixel unit PU are not limited to those in the example illustrated in the figure and are modifiable as appropriate.

10 10 10 10 10 a b a b 3 FIG. 3 FIG. The distance measurement pixel Pa includes a photoelectric conversion section(the photoelectric conversion sectionand the photoelectric conversion sectionin). It can also be said that the distance measurement pixel Pa includes a pixel in which the photoelectric conversion sectionis provided and a pixel in which the photoelectric conversion sectionis provided. The distance measurement pixel Pa has a size equivalent to two pixels. In the example illustrated in, the pixel unit PU includes one distance measurement pixel Pa and two imaging pixels Pb, and has a region of 2×2 pixels.

10 10 10 20 30 10 10 10 10 a b a b a b 3 FIG. The distance measurement pixel Pa includes the photoelectric conversion section(the photoelectric conversion sectionand the photoelectric conversion sectionin), an amplification circuit, and an AD conversion circuit, and is configured to detect entering light. The photoelectric conversion sectionand the photoelectric conversion sectionare each configured to receive light and generate a signal. The photoelectric conversion sectionsandare each a light receiving section (a light receiving element) and configured to generate an electric charge by photoelectric conversion.

10 10 10 10 a b a b 3 FIG. For example, the photoelectric conversion sectionsandare each a photodiode (PD) and convert entering light into an electric charge. In the example illustrated in, the photoelectric conversion sectionsandare a balanced photodiode and are electrically coupled in series with each other.

10 10 10 10 10 200 10 10 10 a b a b b a b a The photoelectric conversion sectionand the photoelectric conversion sectioneach make it possible to receive light, generate an electric charge by photoelectric conversion, and output a photocurrent. One of the photoelectric conversion sectionsand, for example, the photoelectric conversion section, is configured to receive the reference light from the light source sectiondescribed above. Another of the photoelectric conversion sectionand the photoelectric conversion section, for example, the photoelectric conversion section, is configured to receive the reflected light from the measurement target.

10 10 200 10 10 a b a b The distance measurement pixel Pa is configured to output, by the photoelectric conversion sectionand the photoelectric conversion section, a distance measurement signal based on the optical signal that is the reference light from the light source sectionand the reflected light that is the optical signal reflected from the object. For example, in response to a reception of the reference light and the reflected light, a signal corresponding to a photocurrent Ia outputted by the photoelectric conversion sectionand the photoelectric conversion sectionis generated and outputted as a distance measurement signal.

20 10 20 10 10 20 10 10 3 FIG. a b a b. The amplification circuitis configured to generate a signal based on the photocurrent outputted by the photoelectric conversion section. In the example illustrated in, the amplification circuitis provided with respect to the photoelectric conversion sectionand the photoelectric conversion section. The amplification circuitis configured to output a signal based on the photocurrent Ia generated by the photoelectric conversion sectionsand

20 20 10 10 3 FIG. a b. For example, the amplification circuit(an amplifying section) includes a transimpedance amplifier (TIA: Transimpedance Amplifier) and is configured to convert a current signal into a voltage signal. In the example illustrated in, the amplification circuitincludes a TIA circuit and is electrically coupled to a node that couples the photoelectric conversion sectionand the photoelectric conversion section

20 10 10 30 200 a b The amplification circuitmakes it possible to convert the current signal generated by the photoelectric conversion sectionand the photoelectric conversion sectioninto a voltage signal, and to output the distance measurement signal that is the voltage signal to the AD conversion circuit. The distance measurement signal has a frequency corresponding to a frequency difference between the optical signal that is the output light from the light source sectionand the optical signal that is the reflected light from the measurement target.

30 30 220 20 30 10 10 a b. The AD conversion circuitis configured to convert an inputted analog signal into a digital signal. The AD conversion circuitis an ADC (Analog to Digital Converter). In the pixel array, it is possible to provide the amplification circuitand the AD conversion circuitfor each distance measurement pixel Pa including the photoelectric conversion sectionand the photoelectric conversion section

3 FIG. 30 20 30 30 230 In the example illustrated in, the distance measurement signal is inputted to the AD conversion circuit(the AD conversion section) from the amplification circuit. The AD conversion circuitperforms sampling on the distance measurement signal and converts the distance measurement signal that is an analogue signal into a digital signal. The AD conversion circuitmakes it possible to output, to the signal processing section, the distance measurement signal converted into a digital signal at each sampling point.

11 40 50 60 1 11 2 40 50 3 50 60 The imaging pixel Pb includes a photoelectric conversion section, a transistor SHG, an amplification circuit, a memory circuit, and a readout circuit, and is configured to detect entering light. The imaging pixel Pb includes a node Nto which the photoelectric conversion sectionand the transistor SHG are coupled, a node Nto which the amplification circuitand the memory circuitare coupled, and a node Nto which the memory circuitand the readout circuitare coupled.

11 11 11 11 11 3 FIG. The photoelectric conversion sectionis configured to receive light and generate a signal. The photoelectric conversion sectionis a light receiving section (a light receiving element) and is configured to generate an electric charge by photoelectric conversion. It is possible for the photoelectric conversion sectionto receive light, generate an electric charge by photoelectric conversion, and output a photocurrent Ib. In the example illustrated in, the photoelectric conversion sectionis a photodiode (PD). The photoelectric conversion sectionperforms photoelectric conversion and generate an electric charge in accordance with the amount of light received.

11 11 11 11 3 FIG. 3 FIG. The transistor SHG is configured to reset the electric charge of the photoelectric conversion section. In the example illustrated in, the transistor SHG is electrically coupled to the reference potential line and is configured to reset the photoelectric conversion section. In the example illustrated in, the reference potential line is an earthing line (a ground line). The transistor SHG allows the electric charge accumulated in the photoelectric conversion sectionto be reset, thus resetting the voltage of the photoelectric conversion section. For example, the transistor SHG includes a PMOS transistor.

40 11 40 40 11 The amplification circuitis configured to generate a signal based on the photocurrent outputted by the photoelectric conversion section. For example, the amplification circuit(the amplifying section) includes a TIA circuit. The amplification circuitis configured to output a signal based on the photocurrent Ib generated by the photoelectric conversion section.

3 FIG. 40 1 1 In the example illustrated in, the amplification circuitincludes a transistor AMP, a transistor LM, a transistor RST, and a capacitor Cfb. For example, the transistor AMPincludes a PMOS transistor, and the transistor LM includes an NMOS transistor.

1 1 1 1 1 The transistor AMPhas a gate coupled to the node N. The transistor AMPhas a source electrically coupled to the power supply line to which the supply voltage is supplied. The transistor LM is electrically coupled in series with the transistor AMP. The transistor LM makes it possible to generate an electric current in accordance with the signal level of the signal inputted to the gate and to supply the generated electric current to the transistor AMP.

1 40 2 40 1 2 The capacitor Cfb is provided between the node Nthat is to be an input section of the amplification circuitand the node Nthat is to be an output section of the amplification circuit. The capacitor Cfb has a predetermined capacitance value and is configured to hold a voltage. One electrode of the capacitor Cfb is coupled to the node N. Another electrode of the capacitor Cfb is coupled to the node N. For example, the capacitor Cfb includes a MOS capacitance, a MIM (Metal-Insulator-Metal) capacitance, or the like.

1 40 2 40 40 The transistor RST is provided between the node Nthat is the input section of the amplification circuitand the node Nthat is the output section of the amplification circuit, and is configured to electrically couple the input section and the output section of the amplification circuit. For example, the transistor RST includes an NMOS transistor.

40 40 40 50 40 11 40 11 50 The amplification circuitis configured to convert a current signal into a voltage signal. The amplification circuitis a TIA circuit configured using the capacitor Cfb and is referred to as a CTIA (Capacitive Trans Impedance Amplifier) circuit. It is to be noted that the amplification circuitand the memory circuittogether can also be referred to as a CTIA circuit. The amplification circuitconverts the current signal generated by the photoelectric conversion sectioninto a voltage signal. The amplification circuitmakes it possible to generate a voltage signal in accordance with the amount of light received in the photoelectric conversion section, and to output the voltage signal to the memory circuit.

50 11 50 1 4 1 2 50 40 11 11 3 FIG. The memory circuitis configured to hold the signal based on the photocurrent outputted by the photoelectric conversion section. In the example illustrated in, the memory circuitincludes a switch SWto SW, a capacitor C, and a capacitor C. The memory circuitis configured to hold a signal generated by the amplification circuiton the basis of the photocurrent Ib of the photoelectric conversion section, that is, a voltage signal corresponding to the amount of light received in the photoelectric conversion section.

1 40 1 40 1 2 1 60 1 60 The switch SWis provided between the output section of the amplification circuitand the capacitor C, and is configured to electrically couple the output section of the amplification circuitand the capacitor C. In addition, the switch SWis provided between the capacitor Cand the readout circuit, and is configured to electrically couple the capacitor Cand the readout circuit.

3 40 2 40 2 4 2 60 2 60 The switch SWis provided between the output section of the amplification circuitand the capacitor C, and is configured to electrically couple the output section of the amplification circuitand the capacitor C. In addition, the switch SWis provided between the capacitor Cand the readout circuit, and is configured to electrically couple the capacitor Cand the readout circuit.

1 2 3 4 50 1 2 3 4 Each switch (the switch SW, SW, SW, or SW) of the memory circuitincludes a transistor. For example, each of the switch SW, the switch SW, the switch SW, and the switch SWincludes an NMOS transistor.

1 2 1 2 1 2 The capacitors Cand Care each configured to hold a voltage. For example, the capacitors Cand Ceach include a MOS capacitance, an MIM capacitance, or the like. It is to be noted that the transistor SHG described above allows the electric charge accumulated in each of the capacitors Cand Cto be discharged via the transistor RST.

1 1 1 2 3 2 The transistor SHG allows the electric charge accumulated in the capacitor Cto be reset via the transistor RST and the switch SW, thus resetting the voltage of the capacitor C. In addition, the transistor SHG allows the electric charge accumulated in the capacitor Cto be reset via the transistor RST and the switch SW, thus resetting the voltage of the capacitor C.

60 11 60 2 2 50 3 FIG. The readout circuitis configured to output a signal based on the photocurrent outputted by the photoelectric conversion section. In the example illustrated in, the readout circuitincludes a transistor AMPand a transistor SEL. The transistor AMPis configured to generate and output a signal based on the voltage held in the memory circuit.

3 FIG. 2 50 2 40 50 11 2 2 As illustrated in, the transistor AMPhas a gate electrically coupled to the memory circuit. To the gate of the transistor AMP, the voltage signal converted by the amplification circuitand the memory circuiton the basis of the photocurrent Ib of the photoelectric conversion sectionis inputted. The transistor AMPhas a drain coupled to the power supply line to which the power supply voltage is supplied, and the AMPhas a source coupled to the signal line VSL via the transistor SEL.

2 65 65 2 65 2 The transistor AMPhas a source electrically coupled with a current sourceprovided with respect to the signal line VSL. The current sourceis configured to supply an electric current to the transistor AMP. For example, the current sourceis included in a source follower circuit together with the transistor AMP.

2 50 1 2 60 65 The transistor AMPis configured to generate a signal based on the voltage held in the memory circuit, that is, a signal based on the voltage held in the capacitor Cor the capacitor C, and to output the signal to the signal line VSL. It is to be noted that the readout circuitmay include the current source.

2 The transistor SEL is configured to control an output of the pixel signal. The transistor SEL is configured to output the signal from the transistor AMPto the signal line VSL. The transistor SEL makes it possible to control an output timing of the signal of the imaging pixel Pb.

1 4 230 1 230 50 For example, the transistor SHG, the transistor RST, the transistor SEL, the switches SWto SWor the like of the imaging pixel Pb are controlled to be turned on and off by the signal processing sectionof the photodetector. The signal processing sectioncontrols each switch of the transistor SHG, the transistor RST, the transistor SEL, and the memory circuit, thereby causing a signal to be outputted from the imaging pixel Pb to the signal line VSL.

3 1 2 2 4 2 2 For example, when the transistor SHG, the transistor RST, and the switch SWare turned on (into a conductive state), the node N, the node N, and the capacitor Care electrically coupled together, to reset the electric charge accumulated in the imaging pixel Pb. In a case where the switch SWis turned on, the transistor AMPand the transistor SEL output, as a signal Sp, a signal corresponding to the voltage held in the capacitor Cto the signal line VSL. The signal Sp becomes a signal indicating a reset level (a reference level).

1 2 1 40 1 11 In a case where the transistor SHG and the transistor RST are turned off (into a non-conductive state) and the switch SWis turned on, the node Nand the capacitor Care electrically coupled together, to cause the amplification circuitto supply the capacitor Cwith the voltage corresponding to the photocurrent Ib generated by the photoelectric conversion section.

11 1 2 1 2 2 1 During a charge accumulation period (an exposure period), the voltage corresponding to the amount of light received in the photoelectric conversion sectionis inputted to the capacitor Cand held therein. When the switch SWis turned on, the voltage held in the capacitor Cis inputted to the transistor AMP. The transistor AMPand the transistor SEL output, as a signal Sd, a signal corresponding to the voltage held in the capacitor Cto the signal line VSL. The signal Sd is an imaging signal based on the amount of light received from the measurement target.

230 230 230 The signal outputted from each imaging pixel Pb is inputted to the signal processing sectionvia the signal line VSL. The signal processing sectionperforms signal processing such as AD conversion or correlated double sampling on the signal Sd and the signal Sp of the imaging pixel Pb. As one example, the signal processing sectionmakes it possible to perform CDS processing to subtract the signal Sp from the signal Sd, and to obtain an imaging signal after the CDS processing.

220 230 11 1 Controlling the transistor SHG in each pixel unit PU in the pixel arrayallows the signal processing sectionto reset the photoelectric conversion sectionin all imaging pixels Pb simultaneously. The photodetectormakes it possible to align an imaging timing in each imaging pixel Pb, thus enabling global shutter performance.

1 1 As described above, the photodetectoraccording to the present embodiment includes the pixel unit PU configured to output an imaging signal and a distance measurement signal. This makes it possible for the photodetectorto obtain an imaging signal and a distance measurement signal, and to generate the image data of the subject and the distance image data. For example, it becomes possible to obtain an infrared image of the subject, distance data and speed data of the measurement target, or the like.

Providing the pixel unit PU including the distance measurement pixel Pa and the imaging pixel Pb makes it possible to generate a distance measurement signal and an imaging signal using a common optical system. Compared with a case where the pixel for distance measurement and the pixel for imaging are provided in separate devices and separate optical systems are used, it is possible to reduce a processing load in the case of signal synthesis processing.

1 The photodetectormakes it possible to generate a distance measurement signal and an imaging signal using a common optical system, thus suppressing an increase in the load of signal synthesis between the imaging signal and the distance measurement signal (for example, the load of processing to associate gray scale information with distance information). It becomes possible to prevent a complication in an algorithm, a decrease in signal accuracy, an increase in signal processing time, or the like.

1 220 220 In the photodetectoraccording to the present embodiment, a plurality of pixel units PU is provided repeatedly in an entire surface of the pixel array. This makes it possible to obtain an imaging signal and a distance measurement signal from an entire surface of the pixel array, thus making it possible to perform a measurement of the object with high accuracy.

20 40 In addition, the distance measurement pixel Pa and the imaging pixel Pb in each pixel unit PU include, respectively, the amplification circuitand the amplification circuiteach of which enables amplification of a signal. This makes it possible to increase a sensitivity to entering light, and to increase an accuracy of light detection. It becomes possible to improve image quality.

30 Furthermore, in the present embodiment, the distance measurement pixel Pa has a region equivalent to two pixels as described above. In the distance measurement pixel Pa, it is possible to secure a region in which the AD conversion circuitis to be disposed. This makes it possible to increase the resolution of the AD conversion circuit, that is, the number of bits of AD conversion, and to improve the accuracy of the AD conversion of the distance measurement signal. Thus, it becomes possible to measure the distance to the measurement target, the speed of the measurement target, or the like with high accuracy.

4 FIG. 4 FIG. 1 100 110 115 116 120 1 100 110 115 116 120 is a diagram illustrating an example of a cross-sectional configuration of the photodetector according to the first embodiment. As illustrated in, the photodetectorincludes a photoelectric conversion layer, a semiconductor layer, a wiring layer, a wiring layer, and a semiconductor layer. The photodetectorhas a configuration in which the photoelectric conversion layer, the semiconductor layer, the wiring layer, the wiring layer, and the semiconductor layerare stacked.

100 10 10 10 11 100 100 100 100 a b In the photoelectric conversion layer, the photoelectric conversion section(the photoelectric conversion sectionand the photoelectric conversion section) of each distance measurement pixel Pa and the photoelectric conversion sectionof each imaging pixel Pb described above are provided. For example, the photoelectric conversion layerincludes InGaAs. The photoelectric conversion layermay include another compound semiconductor material. The photoelectric conversion layermay include germanium (Ge), silicon germanium (SiGe), or the like or may include another material. The photoelectric conversion layermay include a quantum dot.

10 11 100 81 82 81 82 81 82 The photoelectric conversion sectionand the photoelectric conversion sectioneach include the photoelectric conversion layer, a protective film, and a protective film. The protective filmand the protective filmare each a passivation film (a protective layer) and each include, for example, InP. It is to be noted that the protective filmand the protective filmmay be formed using a compound semiconductor material, such as an InP-based material, a GaAs-based material, or an SiGe-based material, or may be configured using another material.

81 82 100 81 82 100 81 100 82 100 100 81 82 100 4 FIG. The protective filmand the protective filmare disposed to sandwich the photoelectric conversion layer. The protective filmand the protective filmare provided to be opposed to each other to sandwich the photoelectric conversion layer. In the example illustrated in, the protective filmis a protective film in an upper portion of the photoelectric conversion layer, and the protective filmis a protective film in a lower portion of the photoelectric conversion layer. It is to be noted that the photoelectric conversion layerand the protective filmsandtogether can also be referred to as the photoelectric conversion layer.

110 120 110 120 110 115 110 120 116 120 For example, the semiconductor layerand the semiconductor layerare each a silicon layer including silicon. The semiconductor layerand the semiconductor layermay include another semiconductor material. It is to be noted that the semiconductor layerand the wiring layertogether can also be referred to as the semiconductor layer(or the silicon layer). In addition, the semiconductor layerand the wiring layertogether can also be referred to as the semiconductor layer(or the silicon layer).

115 116 115 116 115 116 For example, the wiring layerand the wiring layereach include a conductor film and an insulating film and have a plurality of wires and vias (VIA) or the like. For example, the wiring layerand the wiring layerinclude two or more wiring layers. Each of the wiring layerand the wiring layerhas a configuration in which a plurality of wirings is stacked with an insulating film in between. It can also be said that this insulating film is an interlayer insulating film (an interlayer insulating layer).

115 116 115 116 The wiring of each of the wiring layersandis formed, for example, using a metallic material such as aluminum (Al), copper (Cu), tungsten (W), or the like. The wiring in the wiring layersandmay be configured using polysilicon (Poly-Si) or another conductive material. The interlayer insulating film is formed using, for example, silicon oxide (SiO), silicon nitride (SiN), silicon oxynitride (SiON), or the like.

110 115 20 40 110 4 FIG. For example, in the semiconductor layerand the wiring layer, the amplification circuit, the transistor SHG, the amplification circuit, or the like described above are provided. For example, as schematically illustrated in, an element such as a transistor including a source region, a drain region, a gate electrode, or the like is formed on a side of one surface of the semiconductor layer.

120 116 30 50 60 230 120 116 In addition, for example, in the semiconductor layerand the wiring layer, the AD conversion circuit, the memory circuit, and the readout circuitdescribed above are provided. It is to be noted that it is possible, for example, to provide the signal processing sectiondescribed above in the semiconductor layerand the wiring layer.

110 115 91 92 91 10 110 10 91 20 110 115 In the semiconductor layerand the wiring layer, an electrodeand an electrodeare provided. The electrodeis a contact and electrically couples the photoelectric conversion sectionand a circuit provided in the semiconductor layer. For example, the photoelectric conversion sectionis electrically coupled via the electrodeto the amplification circuitprovided in the semiconductor layerand the wiring layer.

92 11 110 11 40 110 115 92 The electrodeis a contact and electrically couples the photoelectric conversion sectionand a circuit provided in the semiconductor layer. For example, the photoelectric conversion sectionis electrically coupled to the amplification circuitprovided in the semiconductor layerand the wiring layervia the electrode.

95 115 96 116 95 96 95 96 95 96 In addition, the electrodeis provided in the wiring layer, and the electrodeis provided in the wiring layer. For example, the electrodesandare each an electrode formed using copper (Cu). The electrodeand the electrodeare each an electrode used for bonding between metal electrodes, and it can also be said that the electrodeand the electrodeare a bonding electrode.

95 96 110 120 95 96 110 120 The electrodeand the electrodeelectrically couple the circuit of the semiconductor layerand the circuit of the semiconductor layer. It is to be noted that the electrodesandmay include, for example, a metallic material other than copper, such as nickel (Ni), cobalt (Co), gold (Au), or the like. In addition, the semiconductor layerand the semiconductor layermay be stacked using a bump.

4 FIG. 1 210 1 210 100 210 211 212 In addition, as illustrated in, the photodetectorincludes the optical elementdescribed above. In the photodetector, for example, a plurality of optical elementsis formed to be located above the photoelectric conversion layer. The optical elementincludes the diffraction gratingand the heater.

210 211 212 211 211 211 211 212 As one example, the optical elementincludes the diffraction gratinghaving a plurality of circular holes that is periodically present. The heateris disposed for each diffraction gratingor for each plurality of diffraction gratings, and is provided, for example, at an end of the diffraction grating. For example, the diffraction gratingand the heaterinclude a semiconductor region having the same conductivity type.

4 FIG. 212 120 211 212 211 211 211 For example, as in the example illustrated in, the heateris electrically coupled to the circuit in the semiconductor layerthrough a via or the like, and is configured to energize the diffraction grating. The heaterapplies heat to the diffraction gratingby supplying an electric current, thereby making it possible to change the refractive index of the diffraction gratingand to change the direction of the optical signal emitted from the diffraction grating.

1 10 11 100 As described above, in the photodetectoraccording to the present embodiment, the photoelectric conversion sectionof the distance measurement pixel Pa and the photoelectric conversion sectionof the imaging pixel Pb are provided in the same photoelectric conversion layer. This makes it possible to generate a distance measurement signal and an imaging signal using a common optical system, thereby making it possible to reduce the load on the signal synthesis processing.

5 6 FIGS.and 5 FIG. 200 210 are a diagram describing a layout example of the pixel unit in the imaging device according to the first embodiment. As one example, as illustrated in, the pixel unit PU may be disposed to be perpendicular to a scan direction of the laser light that is the optical signal outputted by the light source sectionand the optical element.

6 FIG. In addition, as another example, as illustrated in, the pixel unit PU may be disposed to be horizontal to the scan direction of the laser light that is an optical signal. It is to be noted that the placement of the pixel unit PU is not limited to the example illustrated in the figure and is modifiable as appropriate.

100 60 11 30 10 A photodetector according to the present embodiment includes a plurality of pixel units (the pixel unit PU) each including a photoelectric conversion layer (the photoelectric conversion layer) configured to output a photocurrent by photoelectric conversion, a readout circuit (the readout circuit) configured to output a first signal based on a first photocurrent (for example, the photocurrent of the photoelectric conversion section) outputted by the photoelectric conversion layer, and an AD conversion circuit (the AD conversion circuit) configured to output a second signal based on a second photocurrent (for example, the photocurrent of the photoelectric conversion section) outputted by the photoelectric conversion layer.

1 60 30 1 In the photodetectoraccording to the present embodiment, a plurality of pixel units PU each including the readout circuitconfigured to output an imaging signal and the AD conversion circuitconfigured to output a distance measurement signal is provided. This enables the photodetectorto obtain an imaging signal and a distance measurement signal from each pixel unit PU. It becomes possible to achieve a photodetector having high detection performance.

Next, a second embodiment of the present disclosure is described. In the following, components similar to those in the above embodiments are denoted by the same numerical references and descriptions thereof are omitted as appropriate.

7 FIG. 20 is a diagram illustrating a configuration example of a pixel unit in a photodetector according to the second embodiment of the present disclosure. The pixel unit PU has a configuration in which the distance measurement pixel Pa and the imaging pixel Pb share the amplification circuit. The pixel unit PU includes one distance measurement pixel Pa and one imaging pixel Pb, and has a size equivalent to two pixels.

1 1 10 10 1 10 1 a b b In addition, the pixel unit PU includes a transistor M. The transistor Mis configured to electrically couple the photoelectric conversion sectionand the photoelectric conversion section. For example, the transistor Mincludes a PMOS transistor. The transistor SHG is electrically coupled to a node that couples the photoelectric conversion sectionand the transistor M. It is to be noted that the transistor SHG may be omitted as necessary.

20 10 50 20 10 10 30 a a b For the amplification circuit, it is possible to generate an imaging signal that is a voltage signal based on the photocurrent outputted by the photoelectric conversion section, and to output the imaging signal to the memory circuit. In addition, the amplification circuitmakes it possible to generate a distance measurement signal that is a voltage signal based on the photocurrent outputted by the photoelectric conversion sectionand the photoelectric conversion section, and to output the distance measurement signal to the AD conversion circuit.

230 1 1 1 1 1 20 10 50 50 60 10 a a. For the signal processing sectionof the photodetector, it is possible to supply the transistor Mwith a signal that controls the transistor M, and to control the transistor Mto be turned on and off. In a case where the transistor Mis in an off state, the amplification circuitmakes it possible to generate an imaging signal that is the voltage signal based on the photocurrent generated by the photoelectric conversion section, and to output the imaging signal to the memory circuit. It is possible to read out, via the memory circuitand the readout circuit, the imaging signal that is based on the photocurrent outputted by the photoelectric conversion section

1 10 10 20 10 10 30 10 10 30 a b a b a b In a case where the transistor Mis in an on state, the photoelectric conversion sectionand the photoelectric conversion sectionare electrically coupled together. The amplification circuitmakes it possible to generate a distance measurement signal that is based on the photocurrent generated by the photoelectric conversion sectionsandincluded in a balanced photodiode, and to output the distance measurement signal to the AD conversion circuit. It is possible to read out the distance measurement signal based on the photocurrent outputted by the photoelectric conversion sectionsandvia the AD conversion circuit.

230 1 50 60 30 230 1 Thus, for the signal processing section, it is possible to control the transistor M, the memory circuit, the readout circuit, the AD conversion circuit, or the like, and to read out the imaging signal and the distance measurement signal. For example, the signal processing sectionmay switch a state of the transistor Mon a frame-by-frame basis to read out the imaging signal and the distance measurement signal.

8 9 FIGS.and 8 FIG. 200 210 are a diagram describing a layout example of a pixel unit in the imaging device according to the second embodiment. As one example, as illustrated in, the pixel unit PU may be disposed to be perpendicular to the scan direction of the laser light that is an optical signal outputted by the light source sectionand the optical element.

9 FIG. In addition, as another example, as illustrated in, the pixel unit PU may be disposed to be horizontal to the scan direction of the laser light that is an optical signal. It is to be noted that the placement of pixel unit PU is not limited to the example illustrated in the figure and is modifiable as necessary.

100 60 10 30 10 a b The photodetector according to the present embodiment includes a plurality of pixel units (the pixel unit PU) each including a photoelectric conversion layer (the photoelectric conversion layer) configured to output a photocurrent by photoelectric conversion, a readout circuit (the readout circuit) configured to output a first signal based on a first photocurrent (for example, the photocurrent of the photoelectric conversion section) outputted by the photoelectric conversion layer, and an AD conversion circuit (the AD conversion circuit) configured to output a second signal based on a second photocurrent (for example, the photocurrent of the photoelectric conversion section) outputted by the photoelectric conversion layer.

1 60 30 1 The photodetectoraccording to the present embodiment includes a plurality of pixel units PU each including the readout circuitconfigured to output an imaging signal and the AD conversion circuitconfigured to output a distance measurement signal. In the case of the present embodiment, it is also possible for the photodetectorto obtain the imaging signal and the distance measurement signal for each pixel unit PU. It becomes possible to achieve a photodetector having high detection performance.

Next, modification examples of the present disclosure are described. In the following, components similar to those in the above embodiments are denoted by the same reference numerals, and descriptions thereof are omitted as appropriate.

10 FIG. 10 3 In the embodiments described above, some configuration examples of the pixel unit PU have been described, but these are only illustrative, and the configuration of the pixel unit PU is not limited to the examples described above.is a diagram describing a configuration example of a pixel unit in a photodetector according to modification example 1 of the present disclosure. For example, as in the example illustrated in FIG., the imaging pixel Pb may include a capacitor C.

3 11 3 3 1 3 40 11 For the capacitor C, it is possible to accumulate the electric charge photoelectrically converted by the photoelectric conversion section. It can also be said that the capacitor Cis a holding section that allows holding an electric charge. For example, it is possible for the capacitor Cto include a capacitance added to the node N. The capacitor Cand the amplification circuitmake it possible to convert the photocurrent outputted by the photoelectric conversion sectioninto a voltage signal.

11 FIG. 11 FIG. 1 40 1 1 As in the example illustrated in, the transistor AMPof the amplification circuitmay be configured using an NMOS transistor. In the example illustrated in, the transistor AMPhas a source electrically coupled with the transistor LM. The transistor LM is included in the source follower circuit together with transistor AMP.

12 13 FIGS.and 12 FIG. 13 FIG. 11 2 are a diagram describing a configuration example of a pixel unit in a photodetector according to modification example 2. As in the example illustrated in, the imaging pixel Pb of the pixel unit PU may include a transistor TRG and a floating diffusion FD. The transistor TRG is configured to electrically couple the photoelectric conversion sectionand the transistor AMP. It is to be noted that the transistor TRG may include, for example, a PMOS transistor, as in the example illustrated in.

11 4 The floating diffusion FD is an accumulation section and is configured to accumulate the transferred electric charge. The floating diffusion FD makes it possible to accumulate the electric charge photoelectrically converted by the photoelectric conversion section. The floating diffusion FD allows the transferred electric charge to be accumulated and converted into a voltage corresponding to a capacitance Cof the floating diffusion FD.

Apparatuses that shoot images for appreciation, including digital cameras and mobile equipment having a camera function Apparatuses for traffic use, including onboard sensors that shoot images of the front, back, surroundings, inside, and so on of an automobile for safe driving such as automatic stop and for recognition of a driver's state, monitoring cameras that monitor traveling vehicles and roads, and distance measurement sensors that measure distances including a vehicle-to-vehicle distance Apparatuses for use in home electrical appliances including televisions, refrigerators, and air-conditioners to shoot images of a user's gesture and bring the appliances into operation in accordance with the gesture Apparatuses for medical treatment and health care use, including endoscopes and apparatuses that shoot images of blood vessels by receiving infrared light Apparatuses for security use, including monitoring cameras for crime prevention and cameras for individual authentication Apparatuses for beauty care use, including skin measuring apparatuses that shoot images of skin and microscopes that shoot images of scalp Apparatuses for sports use, including action cameras and wearable cameras for sports applications and the like Apparatuses for agricultural use, including cameras for monitoring the states of fields and crops For example, the photodetector described above is usable in a variety of cases of sensing light, including visible light, infrared light, ultraviolet light, and X-rays, as follows.

The technology (the present technology) according to the present disclosure is applicable to a variety of products. For example, the technology according to the present disclosure may be achieved as a device mounted on any type of mobile body such as an automobile, an electric vehicle, a hybrid electric vehicle, a motorcycle, a bicycle, a personal mobility, an aircraft, a drone, a vessel, or a robot.

14 FIG. is a block diagram depicting an example of schematic configuration of a vehicle control system as an example of a mobile body control system to which the technology according to an embodiment of the present disclosure can be applied.

12000 12001 12000 12010 12020 12030 12040 12050 12051 12052 12053 12050 14 FIG. The vehicle control systemincludes a plurality of electronic control units connected to each other via a communication network. In the example depicted in, the vehicle control systemincludes a driving system control unit, a body system control unit, an outside-vehicle information detecting unit, an in-vehicle information detecting unit, and an integrated control unit. In addition, a microcomputer, a sound/image output section, and a vehicle-mounted network interface (I/F)are illustrated as a functional configuration of the integrated control unit.

12010 12010 The driving system control unitcontrols the operation of devices related to the driving system of the vehicle in accordance with various kinds of programs. For example, the driving system control unitfunctions as a control device for a driving force generating device for generating the driving force of the vehicle, such as an internal combustion engine, a driving motor, or the like, a driving force transmitting mechanism for transmitting the driving force to wheels, a steering mechanism for adjusting the steering angle of the vehicle, a braking device for generating the braking force of the vehicle, and the like.

12020 12020 12020 12020 The body system control unitcontrols the operation of various kinds of devices provided to a vehicle body in accordance with various kinds of programs. For example, the body system control unitfunctions as a control device for a keyless entry system, a smart key system, a power window device, or various kinds of lamps such as a headlamp, a backup lamp, a brake lamp, a turn signal, a fog lamp, or the like. In this case, radio waves transmitted from a mobile device as an alternative to a key or signals of various kinds of switches can be input to the body system control unit. The body system control unitreceives these input radio waves or signals, and controls a door lock device, the power window device, the lamps, or the like of the vehicle.

12030 12000 12030 12031 12030 12031 12030 The outside-vehicle information detecting unitdetects information about the outside of the vehicle including the vehicle control system. For example, the outside-vehicle information detecting unitis connected with an imaging section. The outside-vehicle information detecting unitmakes the imaging sectionimage an image of the outside of the vehicle, and receives the imaged image. On the basis of the received image, the outside-vehicle information detecting unitmay perform processing of detecting an object such as a human, a vehicle, an obstacle, a sign, a character on a road surface, or the like, or processing of detecting a distance thereto.

12031 12031 12031 The imaging sectionis an optical sensor that receives light, and which outputs an electric signal corresponding to a received light amount of the light. The imaging sectioncan output the electric signal as an image, or can output the electric signal as information about a measured distance. In addition, the light received by the imaging sectionmay be visible light, or may be invisible light such as infrared rays or the like.

12040 12040 12041 12041 12041 12040 The in-vehicle information detecting unitdetects information about the inside of the vehicle. The in-vehicle information detecting unitis, for example, connected with a driver state detecting sectionthat detects the state of a driver. The driver state detecting section, for example, includes a camera that images the driver. On the basis of detection information input from the driver state detecting section, the in-vehicle information detecting unitmay calculate a degree of fatigue of the driver or a degree of concentration of the driver, or may determine whether the driver is dozing.

12051 12030 12040 12010 12051 The microcomputercan calculate a control target value for the driving force generating device, the steering mechanism, or the braking device on the basis of the information about the inside or outside of the vehicle which information is obtained by the outside-vehicle information detecting unitor the in-vehicle information detecting unit, and output a control command to the driving system control unit. For example, the microcomputercan perform cooperative control intended to implement functions of an advanced driver assistance system (ADAS) which functions include collision avoidance or shock mitigation for the vehicle, following driving based on a following distance, vehicle speed maintaining driving, a warning of collision of the vehicle, a warning of deviation of the vehicle from a lane, or the like.

12051 12030 12040 In addition, the microcomputercan perform cooperative control intended for automated driving, which makes the vehicle to travel automatedly without depending on the operation of the driver, or the like, by controlling the driving force generating device, the steering mechanism, the braking device, or the like on the basis of the information about the outside or inside of the vehicle which information is obtained by the outside-vehicle information detecting unitor the in-vehicle information detecting unit.

12051 12020 12030 12051 12030 In addition, the microcomputercan output a control command to the body system control uniton the basis of the information about the outside of the vehicle which information is obtained by the outside-vehicle information detecting unit. For example, the microcomputercan perform cooperative control intended to prevent a glare by controlling the headlamp so as to change from a high beam to a low beam, for example, in accordance with the position of a preceding vehicle or an oncoming vehicle detected by the outside-vehicle information detecting unit.

12052 12061 12062 12063 12062 14 FIG. The sound/image output sectiontransmits an output signal of at least one of a sound and an image to an output device capable of visually or auditorily notifying information to an occupant of the vehicle or the outside of the vehicle. In the example of, an audio speaker, a display section, and an instrument panelare illustrated as the output device. The display sectionmay, for example, include at least one of an on-board display and a head-up display.

15 FIG. 12031 is a diagram depicting an example of the installation position of the imaging section.

15 FIG. 12031 12101 12102 12103 12104 12105 In, the imaging sectionincludes imaging sections,,,, and.

12101 12102 12103 12104 12105 12100 12101 12105 12100 12102 12103 12100 12104 12100 12105 The imaging sections,,,, andare, for example, disposed at positions on a front nose, sideview mirrors, a rear bumper, and a back door of the vehicleas well as a position on an upper portion of a windshield within the interior of the vehicle. The imaging sectionprovided to the front nose and the imaging sectionprovided to the upper portion of the windshield within the interior of the vehicle obtain mainly an image of the front of the vehicle. The imaging sectionsandprovided to the sideview mirrors obtain mainly an image of the sides of the vehicle. The imaging sectionprovided to the rear bumper or the back door obtains mainly an image of the rear of the vehicle. The imaging sectionprovided to the upper portion of the windshield within the interior of the vehicle is used mainly to detect a preceding vehicle, a pedestrian, an obstacle, a signal, a traffic sign, a lane, or the like.

15 FIG. 12101 12104 12111 12101 12112 12113 12102 12103 12114 12104 12100 12101 12104 Incidentally,depicts an example of photographing ranges of the imaging sectionsto. An imaging rangerepresents the imaging range of the imaging sectionprovided to the front nose. Imaging rangesandrespectively represent the imaging ranges of the imaging sectionsandprovided to the sideview mirrors. An imaging rangerepresents the imaging range of the imaging sectionprovided to the rear bumper or the back door. A bird's-eye image of the vehicleas viewed from above is obtained by superimposing image data imaged by the imaging sectionsto, for example.

12101 12104 12101 12104 At least one of the imaging sectionstomay have a function of obtaining distance information. For example, at least one of the imaging sectionstomay be a stereo camera constituted of a plurality of imaging elements, or may be an imaging element having pixels for phase difference detection.

12051 12111 12114 12100 12101 12104 12100 12100 12051 For example, the microcomputercan determine a distance to each three-dimensional object within the imaging rangestoand a temporal change in the distance (relative speed with respect to the vehicle) on the basis of the distance information obtained from the imaging sectionsto, and thereby extract, as a preceding vehicle, a nearest three-dimensional object in particular that is present on a traveling path of the vehicleand which travels in substantially the same direction as the vehicleat a predetermined speed (for example, equal to or more than 0 km/hour). Further, the microcomputercan set a following distance to be maintained in front of a preceding vehicle in advance, and perform automatic brake control (including following stop control), automatic acceleration control (including following start control), or the like. It is thus possible to perform cooperative control intended for automated driving that makes the vehicle travel automatedly without depending on the operation of the driver or the like.

12051 12101 12104 12051 12100 12100 12100 12051 12051 12061 12062 12010 12051 For example, the microcomputercan classify three-dimensional object data on three-dimensional objects into three-dimensional object data of a two-wheeled vehicle, a standard-sized vehicle, a large-sized vehicle, a pedestrian, a utility pole, and other three-dimensional objects on the basis of the distance information obtained from the imaging sectionsto, extract the classified three-dimensional object data, and use the extracted three-dimensional object data for automatic avoidance of an obstacle. For example, the microcomputeridentifies obstacles around the vehicleas obstacles that the driver of the vehiclecan recognize visually and obstacles that are difficult for the driver of the vehicleto recognize visually. Then, the microcomputerdetermines a collision risk indicating a risk of collision with each obstacle. In a situation in which the collision risk is equal to or higher than a set value and there is thus a possibility of collision, the microcomputeroutputs a warning to the driver via the audio speakeror the display section, and performs forced deceleration or avoidance steering via the driving system control unit. The microcomputercan thereby assist in driving to avoid collision.

12101 12104 12051 12101 12104 12101 12104 12051 12101 12104 12052 12062 12052 12062 At least one of the imaging sectionstomay be an infrared camera that detects infrared rays. The microcomputercan, for example, recognize a pedestrian by determining whether or not there is a pedestrian in imaged images of the imaging sectionsto. Such recognition of a pedestrian is, for example, performed by a procedure of extracting characteristic points in the imaged images of the imaging sectionstoas infrared cameras and a procedure of determining whether or not it is the pedestrian by performing pattern matching processing on a series of characteristic points representing the contour of the object. When the microcomputerdetermines that there is a pedestrian in the imaged images of the imaging sectionsto, and thus recognizes the pedestrian, the sound/image output sectioncontrols the display sectionso that a square contour line for emphasis is displayed so as to be superimposed on the recognized pedestrian. The sound/image output sectionmay also control the display sectionso that an icon or the like representing the pedestrian is displayed at a desired position.

12031 1 12031 12031 The description has been given hereinabove of the mobile body control system to which the technology according to an embodiment of the present disclosure is applicable. The technology according to an embodiment of the present disclosure is applicable to the imaging section, for example, of the configurations described above. Specifically, for example, the photodetectoror the like can be applied to the imaging section. Applying the technology according to an embodiment of the present disclosure to the imaging sectionenables obtainment of a photographed image having high definition. This makes it possible to perform highly accurate control utilizing the photographed image in the mobile body control system.

The technology according to an embodiment of the present disclosure (present technology) is applicable to various products. For example, the technology according to an embodiment of the present disclosure may be applied to an endoscopic surgery system.

16 FIG. is a view depicting an example of a schematic configuration of an endoscopic surgery system to which the technology according to an embodiment of the present disclosure (present technology) can be applied.

16 FIG. 11131 11000 11132 11133 11000 11100 11110 11111 11112 11120 11100 11200 In, a state is illustrated in which a surgeon (medical doctor)is using an endoscopic surgery systemto perform surgery for a patienton a patient bed. As depicted, the endoscopic surgery systemincludes an endoscope, other surgical toolssuch as a pneumoperitoneum tubeand an energy device, a supporting arm apparatuswhich supports the endoscopethereon, and a carton which various apparatus for endoscopic surgery are mounted.

11100 11101 11132 11102 11101 11100 11101 11100 11101 The endoscopeincludes a lens barrelhaving a region of a predetermined length from a distal end thereof to be inserted into a body cavity of the patient, and a camera headconnected to a proximal end of the lens barrel. In the example depicted, the endoscopeis depicted which includes as a rigid endoscope having the lens barrelof the hard type. However, the endoscopemay otherwise be included as a flexible endoscope having the lens barrelof the flexible type.

11101 11203 11100 11203 11101 11101 11132 11100 The lens barrelhas, at a distal end thereof, an opening in which an objective lens is fitted. A light source apparatusis connected to the endoscopesuch that light generated by the light source apparatusis introduced to a distal end of the lens barrelby a light guide extending in the inside of the lens barreland is irradiated toward an observation target in a body cavity of the patientthrough the objective lens. It is to be noted that the endoscopemay be a forward-viewing endoscope or may be an oblique-viewing endoscope or a side-viewing endoscope.

11102 11201 An optical system and an image pickup element are provided in the inside of the camera headsuch that reflected light (observation light) from the observation target is condensed on the image pickup element by the optical system. The observation light is photo-electrically converted by the image pickup element to generate an electric signal corresponding to the observation light, namely, an image signal corresponding to an observation image. The image signal is transmitted as RAW data to a CCU.

11201 11100 11202 11201 11102 The CCUincludes a central processing unit (CPU), a graphics processing unit (GPU) or the like and integrally controls operation of the endoscopeand a display apparatus. Further, the CCUreceives an image signal from the camera headand performs, for the image signal, various image processes for displaying an image based on the image signal such as, for example, a development process (demosaic process).

11202 11201 11201 The display apparatusdisplays thereon an image based on an image signal, for which the image processes have been performed by the CCU, under the control of the CCU.

11203 11100 The light source apparatusincludes a light source such as, for example, a light emitting diode (LED) and supplies irradiation light upon imaging of a surgical region to the endoscope.

11204 11000 11000 11204 11100 An inputting apparatusis an input interface for the endoscopic surgery system. A user can perform inputting of various kinds of information or instruction inputting to the endoscopic surgery systemthrough the inputting apparatus. For example, the user would input an instruction or a like to change an image pickup condition (type of irradiation light, magnification, focal distance or the like) by the endoscope.

11205 11112 11206 11132 11111 11100 11207 11208 A treatment tool controlling apparatuscontrols driving of the energy devicefor cautery or incision of a tissue, sealing of a blood vessel or the like. A pneumoperitoneum apparatusfeeds gas into a body cavity of the patientthrough the pneumoperitoneum tubeto inflate the body cavity in order to secure the field of view of the endoscopeand secure the working space for the surgeon. A recorderis an apparatus capable of recording various kinds of information relating to surgery. A printeris an apparatus capable of printing various kinds of information relating to surgery in various forms such as a text, an image or a graph.

11203 11100 11203 11102 It is to be noted that the light source apparatuswhich supplies irradiation light when a surgical region is to be imaged to the endoscopemay include a white light source which includes, for example, an LED, a laser light source or a combination of them. Where a white light source includes a combination of red, green, and blue (RGB) laser light sources, since the output intensity and the output timing can be controlled with a high degree of accuracy for each color (each wavelength), adjustment of the white balance of a picked up image can be performed by the light source apparatus. Further, in this case, if laser beams from the respective RGB laser light sources are irradiated time-divisionally on an observation target and driving of the image pickup elements of the camera headare controlled in synchronism with the irradiation timings. Then images individually corresponding to the R, G and B colors can be also picked up time-divisionally. According to this method, a color image can be obtained even if color filters are not provided for the image pickup element.

11203 11102 Further, the light source apparatusmay be controlled such that the intensity of light to be outputted is changed for each predetermined time. By controlling driving of the image pickup element of the camera headin synchronism with the timing of the change of the intensity of light to acquire images time-divisionally and synthesizing the images, an image of a high dynamic range free from underexposed blocked up shadows and overexposed highlights can be created.

11203 11203 Further, the light source apparatusmay be configured to supply light of a predetermined wavelength band ready for special light observation. In special light observation, for example, by utilizing the wavelength dependency of absorption of light in a body tissue to irradiate light of a narrow band in comparison with irradiation light upon ordinary observation (namely, white light), narrow band observation (narrow band imaging) of imaging a predetermined tissue such as a blood vessel of a superficial portion of the mucous membrane or the like in a high contrast is performed. Alternatively, in special light observation, fluorescent observation for obtaining an image from fluorescent light generated by irradiation of excitation light may be performed. In fluorescent observation, it is possible to perform observation of fluorescent light from a body tissue by irradiating excitation light on the body tissue (autofluorescence observation) or to obtain a fluorescent light image by locally injecting a reagent such as indocyanine green (ICG) into a body tissue and irradiating excitation light corresponding to a fluorescent light wavelength of the reagent upon the body tissue. The light source apparatuscan be configured to supply such narrow-band light and/or excitation light suitable for special light observation as described above.

17 FIG. 16 FIG. 11102 11201 is a block diagram depicting an example of a functional configuration of the camera headand the CCUdepicted in.

11102 11401 11402 11403 11404 11405 11201 11411 11412 11413 11102 11201 11400 The camera headincludes a lens unit, an image pickup unit, a driving unit, a communication unitand a camera head controlling unit. The CCUincludes a communication unit, an image processing unitand a control unit. The camera headand the CCUare connected for communication to each other by a transmission cable.

11401 11101 11101 11102 11401 11401 The lens unitis an optical system, provided at a connecting location to the lens barrel. Observation light taken in from a distal end of the lens barrelis guided to the camera headand introduced into the lens unit. The lens unitincludes a combination of a plurality of lenses including a zoom lens and a focusing lens.

11402 11402 11402 11131 11402 11401 The number of image pickup elements which is included by the image pickup unitmay be one (single-plate type) or a plural number (multi-plate type). Where the image pickup unitis configured as that of the multi-plate type, for example, image signals corresponding to respective R, G and B are generated by the image pickup elements, and the image signals may be synthesized to obtain a color image. The image pickup unitmay also be configured so as to have a pair of image pickup elements for acquiring respective image signals for the right eye and the left eye ready for three dimensional (3D) display. If 3D display is performed, then the depth of a living body tissue in a surgical region can be comprehended more accurately by the surgeon. It is to be noted that, where the image pickup unitis configured as that of stereoscopic type, a plurality of systems of lens unitsare provided corresponding to the individual image pickup elements.

11402 11102 11402 11101 Further, the image pickup unitmay not necessarily be provided on the camera head. For example, the image pickup unitmay be provided immediately behind the objective lens in the inside of the lens barrel.

11403 11401 11405 11402 The driving unitincludes an actuator and moves the zoom lens and the focusing lens of the lens unitby a predetermined distance along an optical axis under the control of the camera head controlling unit. Consequently, the magnification and the focal point of a picked up image by the image pickup unitcan be adjusted suitably.

11404 11201 11404 11402 11201 11400 The communication unitincludes a communication apparatus for transmitting and receiving various kinds of information to and from the CCU. The communication unittransmits an image signal acquired from the image pickup unitas RAW data to the CCUthrough the transmission cable.

11404 11102 11201 11405 In addition, the communication unitreceives a control signal for controlling driving of the camera headfrom the CCUand supplies the control signal to the camera head controlling unit. The control signal includes information relating to image pickup conditions such as, for example, information that a frame rate of a picked up image is designated, information that an exposure value upon image picking up is designated and/or information that a magnification and a focal point of a picked up image are designated.

11413 11201 11100 It is to be noted that the image pickup conditions such as the frame rate, exposure value, magnification or focal point may be designated by the user or may be set automatically by the control unitof the CCUon the basis of an acquired image signal. In the latter case, an auto exposure (AE) function, an auto focus (AF) function and an auto white balance (AWB) function are incorporated in the endoscope.

11405 11102 11201 11404 The camera head controlling unitcontrols driving of the camera headon the basis of a control signal from the CCUreceived through the communication unit.

11411 11102 11411 11102 11400 The communication unitincludes a communication apparatus for transmitting and receiving various kinds of information to and from the camera head. The communication unitreceives an image signal transmitted thereto from the camera headthrough the transmission cable.

11411 11102 11102 Further, the communication unittransmits a control signal for controlling driving of the camera headto the camera head. The image signal and the control signal can be transmitted by electrical communication, optical communication or the like.

11412 11102 The image processing unitperforms various image processes for an image signal in the form of RAW data transmitted thereto from the camera head.

11413 11100 11413 11102 The control unitperforms various kinds of control relating to image picking up of a surgical region or the like by the endoscopeand display of a picked up image obtained by image picking up of the surgical region or the like. For example, the control unitcreates a control signal for controlling driving of the camera head.

11413 11412 11202 11413 11413 11112 11413 11202 11131 11131 11131 Further, the control unitcontrols, on the basis of an image signal for which image processes have been performed by the image processing unit, the display apparatusto display a picked up image in which the surgical region or the like is imaged. Thereupon, the control unitmay recognize various objects in the picked up image using various image recognition technologies. For example, the control unitcan recognize a surgical tool such as forceps, a particular living body region, bleeding, mist when the energy deviceis used and so forth by detecting the shape, color and so forth of edges of objects included in a picked up image. The control unitmay cause, when it controls the display apparatusto display a picked up image, various kinds of surgery supporting information to be displayed in an overlapping manner with an image of the surgical region using a result of the recognition. Where surgery supporting information is displayed in an overlapping manner and presented to the surgeon, the burden on the surgeoncan be reduced and the surgeoncan proceed with the surgery with certainty.

11400 11102 11201 The transmission cablewhich connects the camera headand the CCUto each other is an electric signal cable ready for communication of an electric signal, an optical fiber ready for optical communication or a composite cable ready for both of electrical and optical communications.

11400 11102 11201 Here, while, in the example depicted, communication is performed by wired communication using the transmission cable, the communication between the camera headand the CCUmay be performed by wireless communication.

11402 11102 11100 11402 11100 The description has been given hereinabove of one example of the endoscopic surgery system, to which the technology according to an embodiment of the present disclosure is applicable. The technology according to an embodiment of the present disclosure is suitably applicable to, for example, the image pickup unitprovided in the camera headof the endoscopeof the configurations described above. Applying the technology according to an embodiment of the present disclosure to the image pickup unitmakes it possible to provide the endoscopehaving high definition.

Although the description has been given hereinabove of the present disclosure with reference to the embodiment, the modification examples, the usage example, and the practical application examples, the present technology is not limited to the foregoing embodiment and the like, and may be modified in a wide variety of ways. For example, although the foregoing modification examples have been described as modification examples of the foregoing embodiment, the configurations of the respective modification examples may be combined as appropriate.

A photodetector according to an embodiment of the present disclosure includes a plurality of pixel units each including a photoelectric conversion layer configured to output a photocurrent by photoelectric conversion, a readout circuit configured to output a first signal based on a first photocurrent outputted by the photoelectric conversion layer, and an AD conversion circuit configured to output a second signal based on a second photocurrent outputted by the photoelectric conversion layer. This enables the photodetector to obtain an imaging signal and a distance measurement signal from each pixel unit PU. It becomes possible to achieve a photodetector having favorable performance.

(1) It is to be noted that the effects described herein are merely exemplary and are not limited to the description, and may further include other effects. In addition, the present disclosure may also have the following configurations.

A photodetector including a plurality of pixel units, the plurality of pixel units each including

a photoelectric conversion layer configured to output a photocurrent by photoelectric conversion,

a readout circuit configured to output a first signal based on a first photocurrent, the first photocurrent being outputted by the photoelectric conversion layer, and

(2) an AD conversion circuit configured to output a second signal based on a second photocurrent, the second photocurrent being outputted by the photoelectric conversion layer.

The photodetector according to (1), in which

the readout circuit is configured to output the first signal related to a gray scale value, and

(3) the AD conversion circuit is configured to output the second signal related to a distance to an object.

(4) The photodetector according to (1) or (2), in which the pixel units each include a first amplification circuit and a second amplification circuit, the first amplification circuit being configured to generate a voltage signal based on the first photocurrent, the second amplification circuit being configured to generate a voltage signal based on the second photocurrent.

The photodetector according to (3), in which

the readout circuit is configured to output the first signal based on the voltage signal generated by the first amplification circuit, and

(5) the AD conversion circuit is configured to convert the voltage signal generated by the second amplification circuit into a digital signal, and to output the digital signal as the second signal.

The photodetector according to (3) or (4), in which

the pixel units each include a first photoelectric conversion element and a second photoelectric conversion element, the first photoelectric conversion element and the second photoelectric conversion element being provided in the photoelectric conversion layer,

the first photoelectric conversion element and the second photoelectric conversion element are electrically coupled in series between a power supply line and a reference potential line, and

(6) the second amplification circuit is configured to generate the voltage signal based on the second photocurrent, the second photocurrent being outputted by the first photoelectric conversion element and the second photoelectric conversion element.

The photodetector according to any one of (3) to (5), in which

the pixel units each include a third photoelectric conversion element provided in the photoelectric conversion layer, and

(7) the first amplification circuit is configured to generate the voltage signal based on the first photocurrent outputted by the third photoelectric conversion element.

(8) The photodetector according to any one of (1) to (6), in which the pixel units each include an amplification circuit, the amplification circuit being configured to generate a voltage signal based on the first photocurrent and a voltage signal based on the second photocurrent.

The photodetector according to (7), in which

the readout circuit is configured to output the first signal on a basis of the voltage signal based on the first photocurrent, the first photocurrent being generated by the amplification circuit, and

(9) the AD conversion circuit is configured to output the second signal on a basis of the voltage signal based on the second photocurrent, the second photocurrent being generated by the amplification circuit.

The photodetector according to (7) or (8), in which

the pixel units each include a first photoelectric conversion element, a second photoelectric conversion element, and a transistor, the first photoelectric conversion element and the second photoelectric conversion element being provided in the photoelectric conversion layer, the transistor being coupled between the first photoelectric conversion element and the second photoelectric conversion element, and

(10) the first photoelectric conversion element and the second photoelectric conversion element are electrically coupled in series between a power supply line and a reference potential line via the transistor.

(11) The photodetector according to (9), in which the amplification circuit is configured to generate the voltage signal based on the second photocurrent while the transistor is in an on state, the second photocurrent being outputted by the first photoelectric conversion element and the second photoelectric conversion element.

(12) The photodetector according to (9) or (10), in which the amplification circuit is configured to generate the voltage signal based on the first photocurrent while the transistor is in an off state, the first photocurrent being outputted by the first photoelectric conversion element.

(13) The photodetector according to any one of (1) to (10), further including an optical element configured to output an optical signal.

The photodetector according to (12), in which

the optical element is configured to output the optical signal having a modulated frequency, and

(14) the photoelectric conversion layer is configured to output a photocurrent by photoelectrically converting the optical signal reflected by an object.

(15) The photodetector according to any one of (1) to (13), further including a memory circuit configured to hold a voltage signal based on the first photocurrent, the first photocurrent being outputted by the photoelectric conversion layer.

(16) The photodetector according to (14), in which the readout circuit is configured to output the first signal based on the voltage signal, the voltage signal being held by the memory circuit.

The photodetector according to any one of (1) to (15), further including a semiconductor layer stacked on the photoelectric conversion layer, in which

(17) the readout circuit and the AD conversion circuit are provided in the semiconductor layer.

An electronic apparatus including:

an optical system; and

a photodetector that receives light transmitted through the optical system, in which

the photodetector includes a plurality of pixel units, the plurality of pixel units each including

a photoelectric conversion layer configured to output a photocurrent by photoelectric conversion,

a readout circuit configured to output a first signal based on a first photocurrent, the first photocurrent being outputted by the photoelectric conversion layer, and

an AD conversion circuit configured to output a second signal based on a second photocurrent, the second photocurrent being outputted by the photoelectric conversion layer.

The present application claims the benefit of Japanese Priority Patent Application JP2023-051791 filed with the Japan Patent Office on Mar. 28, 2023, the entire contents of which are incorporated herein by reference.

It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and alterations may occur depending on design requirements and other factors insofar as they are within the scope of the appended claims or the equivalents thereof.